Peter J. Robinson

Non-invasive diagnosis of pulmonary hypertension☆

Although echocardiography provides excellent anatomical and physiological information in cardiac patients, and a proportion of patients now undergo surgery without prior invasive studies [l], a reliable non-invasive method of measuring pulmonary arterial pressure has yet to be developed. Because of this, if accurate knowledge of pulmonary arterial pressure is required, cardiac catheterisation is still necessary in a large number of patients. The development of accurate non-invasive estimation of pulmonary arterial pressure might not only assist diagnosis and avoid catheterisation in some patients, but would also be of considerable value in the intensive care setting. It would also permit repeated measurements in individual patients over a long period of time. Previous approaches have involved measurement of systolic time intervals from the surface electrocardiogram and M-mode or Doppler echocardiography, cross-sectional echocardiography alone, or more recently cross-sectional echocardiography combined with pulsed Doppler and contrast echocardiography. We shall review each of these methods in turn.

Mechanisms of maintained exercise capacity in adults with repaired tetralogy of Fallot

BACKGROUNDnThe mechanisms whereby cardiac output is augmented with exercise in adult repaired tetralogy of Fallot (TOF) are poorly characterised.nnnMETHODSn16 repaired TOF patients (25 ± 7 years of age) and 8 age and sex matched controls (25 ± 4 years of age) underwent cardiopulmonary exercise testing and then real-time cardiac MRI (1.5 T) at rest and whilst exercising within the scanner, aiming for 30% heart rate reserve (Level 1) and 60% heart rate reserve (Level 2), using a custom-built MRI compatible foot pedal device.nnnRESULTSnAt rest, TOF patients had severely dilated RVs (indexed RV end-diastolic volume: 149 ± 37 mL/m(2)), moderate-severe PR (regurgitant fraction 35 ± 12%), normal RV fractional area change (FAC) (52 ± 7%) and very mildly impaired exercise capacity (83 ± 15% of predicted maximal work rate). Heart rate and RV FAC increased significantly in TOF patients (75 ± 10 vs 123 ± 17 beats per minute, p<0.001; 44 ± 7 vs 51 ± 10%, p=0.025), and similarly in control subjects (70 ± 11 vs 127 ± 12 beats per minute, p<0.001; 49 ± 7 vs 61 ± 9%, p=0.003), when rest was compared to Level 2. PR fraction decreased significantly but only modestly, from rest to Level 2 in TOF patients (37 ± 15 to 31 ± 15%, p=0.002). Pulmonary artery net forward flow was maintained and did not significantly increase from rest to Level 2 in TOF patients (70 ± 19 vs 69 ± 12 mL/beat, p=0.854) or controls (93 ± 9 vs 95 ± 21 mL/beat, p=0.648).nnnCONCLUSIONSnDuring exercise in repaired TOF subjects with dilated RV and free PR, increased total RV output per minute was facilitated by an increase in heart rate, an increase in RV FAC and a decrease in PR fraction.

Continuous wave Doppler in the evaluation of simple and complex congenital heart disease in infants and children.

Continuous wave Doppler assessment of systolic pressure gradients was performed using a digital maximal frequency estimator in 118 consecutive infants and children with suspected ventricular outflow obstruction who were undergoing cardiac catheterisation. There was satisfactory correlation with measured systolic pressure gradients in most patients with isolated pulmonary valve stenosis, aortic stenosis or aortic coarctation. Important under-estimation of gradients, however, occurred frequently in patients with more complex lesions. In many of these, the stenotic jet was posteriorly located or obstruction to flow occurred at more than one level. Continuous wave Doppler assessment of outflow tract gradients should be interpreted with caution in complex congenital heart lesions. A low predicted gradient should not be relied upon in isolation for clinical decision making. On the other hand, demonstration of a large gradient by continuous wave Doppler ultrasound provides additional information which may obviate the need for invasive investigation.

Management errors in adults with congenital heart disease: prevalence, sources, and consequences

AimsnImproved survival has resulted in increasing numbers and complexity of adults with congenital heart disease (ACHD). International guidelines recommend specialized care but many patients are still not managed at dedicated ACHD centres. This study analysed referral sources and appropriateness of management for patients referred to our tertiary ACHD Centre over the past 3u2009years.nnnMethods and resultsnWe compared differences in care between patients referred from paediatric/ACHD-trained vs. general adult cardiologists, according to Adherence (A) or Non-Adherence (NA) with published guidelines. Non-Adherent cases were graded according to the severity of adverse outcome or risk of adverse outcome. Of 309 consecutively referred patients (28u2009±u200914u2009years, 51% male), 134 (43%) were from general cardiologists (19% highly complex CHD) and 115 (37%) were from paediatric cardiology or ACHD specialists (33% highly complex CHD). Sixty referrals (20%) were from other medical teams and of those, 31 had been lost to follow-up. Guideline deviations were more common in referrals from general compared to CHD-trained cardiologists (Pu2009<u20090.001). Of general cardiology referrals, 49 (37%) were NA; 18 had catastrophic or major complications (nu2009=u20092, 16 respectively). In contrast, only 12 (10%) of the paediatric/ACHD referrals were NA, but none of these were catastrophic and only 3 were major. Simple, moderate, and highly complex CHD patients were at increased risk of adverse outcome when not under specialized CHD cardiology care (Pu2009=u20090.04, 0.009, and 0.002, respectively).nnnConclusionnNon-adherence with guidelines was common in the ACHD population, and this frequently resulted in important adverse clinical consequences. These problems were more likely in patients who had not been receiving specialized CHD care. Configuring healthcare systems to optimize whole of life care for this growing population is essential.

Sudden cardiac death in adults with congenitally corrected transposition of the great arteries

Background Congenitally corrected transposition of the great arteries (ccTGA) is a rare congenital heart disease. There have been only few reports of sudden cardiac death (SCD) in patients with ccTGA and reasonable ventricular function. Methods A retrospective review of the medical records of all patients attending our adult congenital heart centre, with known ccTGA. Results From a database of over 3500 adult patients with congenital heart disease, we identified 39 (∼1%) with ccTGA and ‘two-ventricle’ circulations. 65% were male. The mean age at diagnosis was 12.4±11.4u2005years and the mean age at last time of review was 34.3±11.3u2005years. 24 patients (56%) had a history of surgical intervention. 8 (19%) had had pacemaker implantation and 2 had had a defibrillator implanted for non-sustained ventricular tachycardia (NSVT). In 544u2005years of patient follow-up, there had been five cases of SCD in our population; 1 death per 109 patient-years. Two of these patients had had previously documented supraventricular or NSVT. However, they were all classified as New York Heart Association (NYHA) class I or II, and systemic (right) ventricular function had been recorded as normal, mildly or mildly–moderately impaired, at most recent follow-up. Conclusions Our experience suggests the need for improved risk stratification and/or surveillance for malignant arrhythmia in adults with ccTGA, even in those with reasonable functional class on ventricular function.

Right Ventricular Mass is Associated with Exercise Capacity in Adults with Repaired Tetralogy of Fallot

The relationship between exercise capacity and right ventricular (RV) structure and function in adult repaired tetralogy of Fallot (TOF) is poorly understood. We therefore aimed to examine the relationships between cardiac MRI and cardiopulmonary exercise test variables in adult repaired TOF patients. In particular, we sought to determine the role of RV mass in determining exercise capacity. Eighty-two adult repaired TOF patients (age at evaluation 26xa0±xa010xa0years; mean age at repair 2.5xa0±xa02.8xa0years; 23.3xa0±xa07.9xa0years since repair; 53 males) (including nine patients with tetralogy-type pulmonary atresia with ventricular septal defect) were prospectively recruited to undergo cardiac MRI and cardiopulmonary exercise testing. As expected, these repaired TOF patients had RV dilatation (indexed RV end-diastolic volume: 153xa0±xa043.9xa0mL/m2), moderate–severe pulmonary regurgitation (pulmonary regurgitant fraction: 33xa0±xa014xa0%) and preserved left (LV ejection fraction: 59xa0±xa08xa0%) and RV systolic function (RV ejection fraction: 51xa0±xa07xa0%). Exercise capacity was near-normal (peak work: 88xa0±xa017xa0% predicted; peak oxygen consumption: 84xa0±xa017xa0% predicted). Peak work exhibited a significant positive correlation with RV mass in univariate analysis (rxa0=xa00.45, pxa0<xa00.001) and (independent of other cardiac MRI variables) in multivariate analyses. For each 10xa0g higher RV mass, peak work was 8xa0W higher. Peak work exhibits a significant positive correlation with RV mass, independent of other cardiac MRI variables. RV mass measured on cardiac MRI may provide a novel marker of clinical progress in adult patients with repaired TOF.

Cross-Sectional Echocardiographic Evaluation of Left Ventricular Outflow Tract Obstruction in Transposition of the Great Arteries with Intact Ventricular Septum

Evaluation of left ventricular outflow tract obstruction in transposition of the great arteries with intact ventricular septum is increasingly important when deciding between an atrial or arterial switch procedure. These gradients may be due to anatomically fixed lesions or to so-called dynamic left ventricular outflow tract obstructions. These dynamic gradients have been previously attributed to systolic anterior motion of the mitral valve [1], high pulmonary blood flow [2], and excessive posterior bulging of the interventricular septum towards the left ventricular cavity [2, 3]. However, systolic anterior motion may be present in the absence of an important left ventricular outflow tract gradient [4], and the role of septal bulge has never been evaluated in living subjects. The purpose of this study was to investigate the anatomic and physiologic factors associated with narrowing of the left ventricular outflow tract in these patients and to relate the findings to the severity of obstruction.